The regulating mechanisms of Triton X-100 affected oxidation of PAHs in site soil aggregates using sodium citrate assisted Fe-persulfate.

Here, we present a first investigation of the inhibition mechanism of surfactant Triton X-100 (TX-100) on the oxidation degradation of polycyclic aromatic hydrocarbons (PAHs) in site soil aggregates using sodium citrate assisted Fe-activated persulfate (SC/Fe/PS). First, TX-100 was not only competed the adsorption sites of soil aggregates with PS, but also consumed PS, which inhibit the PAHs remediation rate in the TX-100 elution followed by the SC/Fe/PS oxidation system from 55.6 % in the oxidation system to 50.3 %. Furthermore, in the oxidation followed by elution system, PAHs was adsorbed on the iron minerals produced during the oxidation, which would be form a bound PAHs that was difficult to react with PS, and then re-eluted to the soil by the TX-100. Additionally, it was found that the oxidative and the elution efficiency of PAHs exhibited negative correlations with aggregate particle sizes. Finally, soil microorganism communities were more strongly changed by SC/Fe/PS oxidation and PAHs concentration than that of TX-100 elution, with obvious alterations bacteria than fungi, the effects of SC/Fe/PS and PAHs concentration on microorganism communities were opposite. This study provided a proof of regulating mechanisms for the site soil remediation using surfactants combined with the iron-PS system.